How can Mastodon server administrators automatically remind their users to add text descriptions?

If you run a Mastodon server, you can easily add a special bit of custom CSS to your server which causes image, video and audio posts without descriptions to have a red border. Here’s how to do it:

  1. Log onto your server’s website with your admin account
  2. Go to ⚙️ Preferences
  3. Go to Administration
  4. Go to Site Settings
  5. Click the Appearance tab at the top
  6. Copy the code from here ⧉ and paste it into the box marked Custom CSS
  7. Click the Save Changes button

This will still allow users to post without descriptions, but the post will have a red border if there’s no alt text.

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How do I add a text description through Mastodon’s edit feature?

There used to be a bug in the edit feature which prevented descriptions being edited. However, the bug was fixed in Mastodon version 4.1.0, so as long as your server is running 4.1.0 or higher then you should be able to edit descriptions just like you would edit the rest of the post.

You can see which version your server is running by going to your server’s website and looking at the bottom of the screen. If you’re on a phone browser, you may need to tap the ⋯ icon and then scroll to the bottom of the screen.

If your server is still running an older version of Mastodon, there is a workaround which does let you add descriptions through editing:

  1. Edit the post
  2. Delete the image
  3. Re-upload the same image
  4. Add the text description
  5. Save changes to the post

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How do I remember to add text descriptions on Mastodon and the Fediverse?

Text descriptions are expected on the Fediverse, it’s seen as good manners to be considerate of screen reader users. By the time you’ve been doing it for a while it becomes second nature, but if you’re not used to adding text descriptions it can be easy to forget to add them.

However, help is available! There is a bot called PleaseCaption which will automatically send you a DM if you’ve forgotten to include an alt text on an image, video or audio post.

  1. Follow the PleaseCaption bot at @PleaseCaptionBot@hachyderm.io ⧉
  2. PleaseCaption will automatically follow you back (if you have follow requests switched on confirm the bot’s request to activate the reminders)
  3. If you post an image, video or audio without a description, PleaseCaption will send you a DM about it as a reminder. You can then edit the post to add the description in if you like.

How do I stop the reminders from PleaseCaption?

To stop the reminders:

  1. Unfollow PleaseCaption
  2. Block and then unblock PleaseCaption, this will remove if as a follower but you will still be able to follow it again in future

How do I delete the reminder DMs from PleaseCaption?

Just favourite a reminder and PleaseCaption will automatically delete it.

Does it check if posts I boost have descriptions?

No, not any more. It used to, but ran into technical difficulties with this feature so the developers have switched boost-checking off for the moment.

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How do I make my posts more accessible to blind, deaf and deafblind people on Mastodon and the Fediverse? How do I add alt texts?

(NOTE: This guide was made with the help of accessibility advocate Robert Kingett, who has also helped with accessibility on many Fediverse volunteer projects such as BookWyrm, GoToSocial and others. You can donate to Kingett via his website ⧉.)

Blind and partially-sighted people on Mastodon and the Fediverse often use special audio apps called “screen readers” that read text out loud, so they can tell what is on the screen.

Blind and deafblind people often use braille displays which convert computer text into refreshable braille ⧉.

Deaf people don’t need screen readers or braille, but they do need text descriptions of any audio content being posted, not just audio files but also videos containing audio.

It is really important to consider accessibility when writing your posts, so that blind, deaf and deafblind people can fully access their content. There are lots of really simple things you can do that make a big difference!

How to add text descriptions (“alt texts”) to image and video and audio posts

  1. Create a new post
  2. Attach an image or video or audio
  3. When the image or video or audio appears in the post editing box, there will be a link somewhere in the image or video itself that says “Alt” or “Description” or “Describe the photo” or something similar, often in a corner. Click on this link.
  4. Write a text description of the image or video or audio. It doesn’t have to describe every detail, you just have to write what you want people to notice. If you’re posting videos containing sound remember to describe both the video and audio.
  5. When you’ve finished writing the description, on some interfaces or apps you may need to click “Apply” or “Done” so you can go back to writing your post. However, some apps let you just click on your post to go back to writing it. Whatever your app or interface uses, do that 🙂
  6. Finish writing your post and publish it

I know this sounds long-winded but you get used to it very quickly. It becomes second nature, and it makes your posts reach a much larger audience!

Why do posts with media descriptions get a much larger audience?

Accessibility is really important on Mastodon and the rest of the Fediverse. A lot of people will not share media posts without descriptions.

If you post media without descriptions, you are making it much harder for people to discover or share your post.

How detailed do alt text descriptions have to be?

This is a matter of context, but the rule of thumb is to just write what is important to notice in an image, video or audio. It doesn’t have to be everything, it just has to be what is relevant.

If you were talking to someone on the phone or writing to someone in a letter, and you had to describe your media post to them in words, what level of detail would you use?

There’s a media post without a description, but it says #Alt4Me in the post. What does this mean?

If you’re abled and you see the hashtag #Alt4Me underneath a media post, it means a disabled person is asking someone to write a description of the media because they are unable to. Reply to the post with the tag #Alt4You and a description.

Also, if you’re an abled person and you see a remarkable piece of media that doesn’t have a description and no one has requested one yet, you can be pro-active and reply with a description using the tag #Alt4You.

What is the image caption group?

As well as the #Alt4Me hashtag, people who need help with creating their media description can mention the Fediverse group @imagecaptionspls@a.gup.pe and abled people who want to help create media descriptions can follow the group.

If someone mention this account in their post, it will be seen by all of the groups followers who can then take action in posting a description in a reply.

What if I’m just posting text? Do I still need to consider accessibility issues?

Yes! Even if you’re just writing a text-only post without any media content, you still need to do a number of things to make your text accessible to blind people using screen readers:

  • When posting hashtags, use CamelCase (where each word begins with a capital letter), for example #DogsOfMastodon instead of #dogsofmastodon. The capital letters allow screen reader apps to separate the words correctly and read the hashtag out loud properly. This also makes the tag easier for sighted people to read!
  • Don’t do that “sarcastic text” thing where you make fun of someone by having random letters as capitals. Random capital letters within words prevent a screen reader from working properly, it reads such words as disjointed gibberish.
  • Don’t use long strings of emoji, as these sound really annoying when read out loud by screen readers. It’s okay to use emoji, it’s just the huge groups of emoji all bunched together that cause problems. Try not to exceed one or two emoji per group if possible.
  • Don’t use deliberately obscure characters for your username, these can sound like gibberish when a screen reader reads them out (click here for an example ⧉). Standard characters work with screen readers, obscure characters usually don’t.

How do I remember to add descriptions to my media posts?

There is an automatic reminder service called PleaseCaption which will remind you by DM if you forget to add an alt text description.

What if I forget to add a description?

You can edit your posts to add descriptions afterwards.

Should I be criticising people who haven’t added alt texts?

It’s important to add descriptions to media so that they’re accessible, but it’s also important not to criticise those who are unable to do so due to their own disability. If someone has written #Alt4Me alongside the media, that means they cannot add descriptions themselves. Don’t criticise them or comment on the lack of description, just help them out by replying with an #Alt4You post which includes your own description of the media item.

If there’s no #Alt4Me tag on the undescribed media, it’s still worth being polite as no one wants bad feelings generated around the topic of descriptions. You might want to just reply with a description and #Alt4You tag, and if they’re abled they will hopefully get the message that descriptions are preferred.

How do I fit the media descriptions into my post without breaking the character limit?

As long as you’re adding the description in the image’s own Alt Text section, it will not count towards your main post’s character limit. There is a large limit for descriptions (1500 characters on Mastodon), so you shouldn’t run out of room.

Also important to remember: accessibility helps everyone!

Accessibility isn’t just about helping the disabled, it makes life easier for everyone.

For example, media descriptions are very, very often viewed by abled people to get a better idea of what the poster is trying to convey. Media descriptions tell people quickly and precisely what the point of the media is. Some posters even include extra details in media descriptions because they have such a high character limit.

Another common example is writing hashtags in CamelCase, as this makes it much easier for everyone to tell which words are in the tag. Sometimes it can be impossible to tell without CamelCase: #superbowl could be #SuperBowl or #SuperbOwl

When we normalise accessibility on the Fediverse, it makes it easier for everyone to use the Fediverse. (A reader has pointed out, this is a well-known phenomenon in the real world called the “curb cut effect” ⧉).

Excuse me, I am a programmer and I’d like to point out that what you call CamelCase is actually PascalCase

There is more info about this terminology issue in the hashtags guide.

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How do I use Mastodon through a screen reader?

Mastodon can be used through screen reader software that converts the text into audio. Here are some useful guides written by blind Mastodon users:

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